Shut-off plug for a blast tip



May 4, 1965 R. LUND SHUT-OFF PLUG FOR A BLAST TIP 2 Sheets-Sheet 1 Filed May 2, 1962 INVENTOR: F$OBERT UND ATT'Y May 4, 1965 R. LUND SHUT-OFF PLUG FOR A BLAST TIP 2 Sheets-Sheet 2 Filed May 2, 1962 INVENTOR. ROBERT LUND United States Patent "ce 3,181,591 SHUT-OFF PLUG FOR A BLAST TB? Robert Lund, Melrose Park, Ill., assignor to Pettibone Mulliken Corporation, Chicago, Ill., a corporation of Delaware Filed May 2, 1962, Ser. No. 191,779 1 Claim. (Cl. 158-404) The present invention relates to foundry equipment and has particular reference to gas-fired heating means for applying heat to a sectional core box during the curing cycle of a molding machine embodying such a core box. More specifically, the invention is concerned with a shut-off plug assembly which is designed for insertion into the combustion chamber of a blast tip in associated relation with the gas manifold of a core box heater unit to the end that such blast tip may be rendered inoperative.

Molding machines for producing hot box cores are widely varied but, in general, and for purposes of discussion herein in connection with the present invention, it may be stated that each such machine involves in its general organization two core box sections which are relatively movable toward and away from each other and, where gas-fired heating means are employed, have associated therewith respective gas manifolds. The latter are provided with a multiplicity of blast tips for producing flame jets which are directed against the core box section during the curing cycle of the machine. Such manifolds are usually provided with blast tip areas which will accommodate heating of the largest core box sections to be used with the machine and thus, when smaller core box sections are installed in the machine, the fringe regions of such blast tip areas supply heat which not only is ineifective to heat the core box sections, but also presents a hazard to the operator when removing the cores from the core box sections during the stripping phase of operations.

To remedy these limitations which are attendant upon the use of continuously burning flame-producing blast tips, some installations have been equipped with individual gas shut-off cocks for the various blast tips, especially the blast tips which occupy a fringe position in the heating areas. However, to render these gas cocks suitable for this use, it has been necessary to plate the working surfaces thereof, particularly the mating valve areas and the journal regions of the gas cock plugs, in order to prevent freezing or sticking of the parts. The use of gas shut-off cocks is extremely costly from the standpoint of the cost of manufacturing the cocks, the cost of plating the working surfaces thereof, and the cost of installation of the cocks and blast tips on the manifolds. It also is not altogether satisfactory since the plating operation does not always render the gas cocks free from sticking after a period of prolonged use. Furthermore, performance of the shut-01f operation on a given number of gas cocks requires the use of a shut-off tool, as well as prolonged reaching on the part of the operator into the heated blast tip areas, especially during manipulation of such gas cocks as are remote from the working area of the operator.

The individual blast tips, as purchased from the manufacturer, are provided with relatively deep socket-like combustion chambers and it has been proposed that, in order to block off the flow of flame-producing gas and thus extinguish the flame jets, simple asbestos or other heat-resistant stoppers be inserted selectively in the combustion chambers of such blast tips to disable the selected blast tips, these stoppers being readily removable by pulling them from the combustion chambers when it is desired again to render the particular blast tips effective. This latter expedient also has presented difliculties in 3,181,591 Patented May 4, 1955 that, despite the low gas manifold pressures involved, the stopper are blown from their seats Within the combustion chambers. For example, a given stopper that will fit within the combustion chamber of a blast tip when cold, will tend to become loose within the chamber when the blast tip becomes heated, this being due to thermal expansion of the metal of the blast tip and a consequent increase in combustion chamber diameter. If the stoppers are made of such large size that they will be tight within the chambers, difficulty is encountered in inserting or removing them. If they are made so that they may readily be inserted, then they will not hold in place under varying temperature conditions. Furthermore, asbestos and other heat-resistant stoppers cannot be held to such close tolerance that out of a large batch thereof all of them are satisfactory and acceptable in use. Finally, if the stoppers are given a frusto-conical shape with a small slant angle so that they will fit within the combustion chambers of the blast tips in the manner of bottle corks, the operator must take pains to see that they are inserted small ends first, this being diflicult due to the small slant angle involved.

The present invention is designed to overcome the above-noted limitations that are attendant upon the construction and use of conventional shut-off means for the blast tips of core box heating gas manifolds and, toward this end, the invention contemplates the provision of a simple and novel shut-off plug assembly which may be manufactured in quantity with little though as to tolerances, which may easily be inserted into and removed from the combustion chamber of a blast tip and which, when installed within the combustion chamber, will maintain a tight frictional grip on the wall of the combustion chamber during wide temperature dilferences, i.e., from a cold condition to a condition of maximum heat. This being among the principal objects of the invention, it is a further object to provide such a shut-off plug assembly in which the proper end for insertion into the combustion chamber is readily recognizable so that there will be no danger of misapplication of the assembly to a blast tip.

Another object of the invention i to provide a shut-off plug assembly which may be applied to an ignited blast tip without requiring that the operators fingers come into close proximity with the flame issuing from such blast tip.

A still further object of the invention is to provide a shut-off plug assembly which includes as a functional element thereof a laminated sealing ring, the ring being capable of replacement in the assembly after it has become worn or otherwise damaged so that the more expensive machined parts of the assembly may be preserved for repeated use with successive or replacement sealing rings.

With these and other objects in view, which will become more readily apparent as the following description ensues, the invention consists in the novel construction, combination and arrangement of parts shown in the accompanying two sheets of drawings forming a part of this specification.

In these drawings:

FIG. 1 is a side elevational view, partly in section, of a molding machine having a core box heating burner with a series of blast tips and showing a number of shutoff plug assemblies embodying the present invention operatively applied thereto;

FIG. 2 is a sectional view taken on the line 22 of FIG. 1;

FIG. 3 is a perspective view of a shut-off plug assembly constructed accord-ing to the principles of the present invention;

FIG. 4 is a front end elevational view of the assembly;

FIG. 5 is an exploded longitudinal sectional view of the assembly; and

FIG. 6 is a fragmentary sectionalview'taken substantially centrally and longitudinally through a blast tip and its associated shut-off plug assembly, showing the latter operatively installed therein, and also showing the blast tip operatively applied to one of the gas manifolds of the molding machine.

Referring now to the drawings in detail and in particu lar to FIGS. 1 and 2, the present invention is shown as being applied to a molding machine only a fragmentary portion of which has been illustrated [and designated in its entirety by the reference numeral 10. Briefly, the molding machine 10 includes two core box sections 12 and 14, each having associated therewith heating means in the form of a gas manifold. The manifold for the core box section 12 is designated by the reference numeral 16 and the manifold for the core box section 14 is designated by the reference numeral 18. a Each manifold is provided witha series of flame-producing blast tips 20 and a series of shut-off. plug assembliesj22. The latter form the subject matter of the present invention and are shown as being applied to certainof the blast tips 20 for the purpose of rendering such tips inoperative. Certain other blast tips have no "shut-off plug assemblies or effective.

and an open core box position which obtains during the stripping phase of machine operation, as is well-known in the Accordingly, the platen 44 carries a horizontal guide sleeve 50 which is slidable'on a horizontal guide rod 51. The latter extends between the manifold 18 anda carriage end plate 52 and constitutes a connecting tie rod between the two parts 18 and 52. A horizon- The details of the molding machine 10 have; not been 5 fully illustrated herein and only such part as will suffice to afford an illustrative environment for the invention have been included in the disclosure of FIGS. 1 and 2. Generally speaking, the molding machine 10 is of the type which is commonly referred to as a roll-lover machineand wherein a rotary squirrel-cage type of carriage structure 24 is rotatably supported in standards 26 and 28. The latter extend upwardly from a suitable base,

(not shown). The core box 14fis reinovably secured to a vertically extending supporting platen 30rin the 'form,

of a grid at the right handend of the carriage structure 24, the platen being fixedly secured in spaced relationship.

to the manifold 18 by means-70ft spacer bolts 32. The

manifold 18 constitutes, in-efiect, one end plate'for the carriage structure and is carried on a hollow shaft 34 having a crank arm 36.v The latter is connected to a' 'fixed within. the carriage structure 2 4'and the former J is provided for the purposeof heating the latter during the curing cycle of the molding machine 10. Accordingly, the manifold 18 'is provided with a series or groups of the blast tips 20 and, as will be described in greater detail hereafter, these tips are adapte'cl'to produce abouttinuously burningseriesof small flame jets and to direct The manifold :18 a

v tal stabilizing bar 54 which is square in cross section presentsvertical side faces which cooperate with friction shoes 56forstabilizing the two manifolds against turning movement within the carriage, structure; a

' Two additional connecting rods 53 pass slidably through thickened portions 55 of the manif0ld 16 as shown in FIG. 2'. The movable manifold 16 is operatively connected to the aforementioned combustion system by a flexible conduit 757 (see FIG. 2). Movement of the three-piece assemblyconsisting of the manifold 16, the

platen 44 and the core box section 12 is effected under the control of a clamp cylinder (not shown) which is mounted upon and turns with the carriage 24 and is provided with'a plunger, a portion of which is shown at .59. .Saidplunger is operatively connected to the. manifold 16. A portion of a sand magazine is shown at 63.

Sand in this magazine is adapted to be charged into the core box by conventional charging apparatus when the corebox sections 12 and 14 are closed upon each other. After the core box has been charged with sand, the curing cycle takes place, and in connection therewith, the heat which is supplied by the flame jets emanating from the blow tips 20 maintains necessary core box temperature for curing of the'sand to produce the core or cores which are to be formed within the core box. After the .cured core has become set, the manifold 16, the platen 44 and-thecore box section 12 are shifted to the 'left as viewed in FIG. 1 in order to render the cured core accessible for removal from the molding machine.

The arrangement of machine parts thusfar described Q-is purely conventional and no claim is made to any novelty associated therewith, thenovelty of the. present invention residing rather in the 'structuralpdetails of the various.

blast tip shut-off assemblies 22 which are employed for selectively rendering certain ofthe blast tips 20 inoperative and will now be more fully described.

Referring now to FIG; 2, it will. be observed that the various blast tips 20 which are associated with the gas manifold 16 are arranged in a predetermined pattern which produces a blast tip area or flame jet region which tips, each.-

The outline of the opposed face of the associated largesized core box section is shown in dotted line at 12' and it will be seen thatthetwelve blast tips 20 which define the jets against the opposed face of the core boxsection 14 at all'times while the machineris in operation 7 The manifold 16 is affixed to a platen 44 by-means of t spacer bolts 46, and the platen 44, inturn, removably carries the core box 12 The manifold: 16, the platen 44 and the core box section 12bear the'same physical rela-,j

tionship to one another that is. evidenced by the manifold 18, the platen 30 and the core box section 14.

The manifold 16, the platen 44 and the core boxlsection 12 are movable bodily as a uni-t toward and away from the manifold 18, the; platen 30 and the core, box section 14 between a closed core box positionwhichfobtains during the filling and curing cycles of machine operation, f

the perimeter of the blast tip pattern fallljust within the marginal confines of such opposed face and thus are effective to heat the, peripheral regions of thisface. Suppose now that this large-sized core box section has sub: stituted therefor the smaller core box section 12 which is illustrated in FIG. ,Land the outline of which has been indicated in bro ken'linesin FIGQ Z, and suppose also that the horizontal venticaldiine'nsions of the opposed face of this section 12 are only halfgthe horizontal and vertical-dimensions, respectively, of the'opposed face 12';

impinge upon the'vopposed facel of the core box section 12. These perimeter blast tips, therefore, represent an appreciable waste of fuel gas, besides constituting a hazard to an operator at such time as he must reach well within the confines of the blast tip area for core removal purposes. The blast tip shut-oif assemblies 22 of the present invention are designed to afford a quick and convenient means for rendering such superfluous or perimeter blast tips inoperative when their heating effect is not required and for restoring them to usefulness when their heating effect is again required. In large installations employing, for example, fifty or more blast tips for producing a large flame jet area, by the selective placement of the shut-off assemblies, not only may the size of this area be reduced or enlarged at will, but the pattern shape of the area may be changed as, for example, to accommodate heating of an opposed core box face which has a circular outline.

The blast tips are conventional or proprietary items and each (see FIG. 6) is in the form of a two-piece assembly comprising a generally cylindrical tubular steel sleeve 60 which is provided with an internal cylindrical bore 61 and has at its outer end a polygonal flange 60a whereby it may be gripped by a wrench or other suitable installation tool. threaded as at 64 for threaded reception in a threaded hole 63 in the wall of the associated gas manifold. Press fitted within the threaded inner end of the sleeve 60 is a relatively thick, generally cylindrical steel head 62. The latter has formed therein a series of drilled ports which may be disposed in any desired pattern but which in the exemplary form of blast tip illustrated herein include a stnaight axial central port 65 and eccentric proximate ports 66 and distal ports 68. The last mentioned ports are offset from the proximate ports and communicate with the latter by way of an annular groove 70. The portion or section of the head 62 which is forward of the groove 70 is of slightly smaller :diameter than the internal diameter of the sleeve 60 in order that there is formed a narrow annulus 72 which establishes connnunication between the groove 70 and the forward region of the bore 61. This forward region of the bore 61, in combination with the front end face of the head 62, establishes a combustion chamber 74 which, in effect, is in the form of a relatively deep socket having a smooth cylindrical wall surface. The herein described arrangement of parts of the blast tip 20 and the relatively low gas pressure in the manifold 44 are such that the flame initiated within the combustion chamber 74 is sufficiently long that it will pass through the grid-like platen 44 and reach the opposed face of the core box section 12 for effective heating of the latter.

The disposition of blast tips 20 in the gas manifold 18 may be similar to that of the blast tips in the gas manifold 16 so that a detailed description of such disposition is unnecessary herein.

According to the present invention, novel means is provided whereby the various blast tips 20 may be selectively disabled at will. This means takes the form of a series of the shut-off plug assemblies, one of which has been shown in detail in FIGS. 3, 4 and 5. These plug assemblies are of elongated design. They are adapted to have their forward end regions inserted into the smooth-walled cylindrical combustion chambers of selected blast tips where they are received with a frictional fit and serve to block the flow of gas through the associated blast tips. In effect, they are in the form of specially designed stoppers" which may be pushed into or withdrawn at will from the sockets which are afforded by the various combustion chambers 74.

Each shut-off plug assembly 22 consists of but three parts, namely, a composite sealing plug proper 80, a handle 82 there-for and a clamping bolt 84 by means of which the plug proper 80 is fixedly but removably secured to the handle.

The inner end of the sleeve is externally The handle 82 is in the form of an elongated cylindrical body which may be formed of metal, preferably a lightweight metal, such as aluminum or an aluminum alloy. The outer one end region of the handle is knurled as at 86 to facilitate gripping and manipulation of the handle 82. The imier end region of the handle is provided with a short reduced section 88 which presents a circular end face 90 having a threaded or tapped socket 92 formed therein. The threaded socket 92 is provided for the purpose of receiving therein the threaded shank portion 94 of the clamping bolt 84 by means of which the plug proper is securely clamped against the end face 90. The clamping bolt 84 is provided with an enlarged head 98 which presents an inside annular shoulder 100. The plug proper 80 is interposed between this shoulder and the end face 90.

The plug proper 80 is a laminated structure and consists of a series of flat, circular washer-like disks 102. The latter are hereinafter referred to as washers and have central hole-s 104 which are in register with one another and through which the shank portion 94 of the clamping bolt 84 extends. The washers 102 are compressed together to form the composite plug proper 80, the outside face of one endmost Washer bearing against the annular shoulder 100 and the outside face of the other endmost washer bearing against the end face of the handle 82. To facilitate tightening of the head 98 of the bolt 34 against the plug proper 80, the head is provided with a kerf 106 for reception of a tightening tool, such as a screw driver or the like. While in the exemplary form of the invention illustrated herein, six of the washerlike disks have been shown, obviously of greater or a lesser number thereof may be employed. The number of disks and the thicknesses thereof will be selected so that a certain amount of individual flexibility is offered by each disk.

The various washers 102 are formed of a suitable flexible, heat-resistant material, such as asbestos, or an asbestos composition, either pressed or woven. These washers may be individually impregnated with a suitable bonding agent or, if sufiiciently tightly woven, the bonding agent is not necessary. Alternatively, the washers may be formed of a moldable material, such as a silicone-treated elastorner or other similar durable heat-resistant substance. Irrespective, however, of the particular material of which the washers may be formed, the essential features of the invention are at all times preserved.

The washers are flexible and the external or maximum outside diameter of each washer is slightly in excess of the maximum diameter of the handle 82 and appreciably in excess of the diameter of the reduced section 88. The outside diameter of these washers is also slightly in excess of the internal diameter of the smooth wall surface of the combustion chamber 74. The frictional characteristics of the material from which the washers 1112 are formed is so related to the diameter of the washers that, when the forward end region of the plug assembly 22 is thrust into the combustion chamber of one of the blast tips 20 and the assembly is then released, the assembly will be self-sustained within the combustion chamber against any tendency for the internal pressure of gas within the associated manifold to have a popgun effect upon the plug assembly and force the same from the combustion chamber. The difference in diameters between the smooth wall of the combustion chamber 74 and the bandie 82 is so small that only a very small amount of axial misalignment between the handle and combustion chamber is possible. The washer-formed plug proper 80 is thus at all times positioned substantially in transverse relationship to the axis of the combustion chamber so that the frictional forces exerted at all peripheral regions of the plug proper 89 against the wall 76 will be equalized while, at the same time, an effective gas seal at these regions will obtain.

Referring again to FIG. 2, in the use of the plug 'a-ssemblies 22, these assemblies are. selectively receivable int-he various combustion chambers oithe blast tips 20; so that the blast, tip pattern mayabe varied to acconnnodatedit- I fering sizesand shapes ofcore box sections. Asprevious- 1y described, thev four innermost blast tips 2 il wit hin the overall blast tip pattern are devoid of plug assemblies 22 7 since it is necessary that theyfunctionto produce flame 7 jets which will impinge upon the opppsedface of the adjacent corebox sectign, However, the twelve blast tips 20 which define the perimeter of the blast tip patte nhave associated therewith respectiye plug assemblies 2-2. These 7 8 Having thus described the invention what I claim as e an desi e t cur b 'L ter Pa en a a 1. a o r ur a b rne a mb y h ina i with aflame-producing blast tip in the form of a tubular sleeve having an axially extending smooth cylindrical-bore therethrough, and a cylindrical head disposed within said 'bore and closing one en'd the'reof, said headbeing forrned with a plurality of gas passages therethrough, the for- :Ward face of said head terminating short of the other plug assemblies obstruct theflow of fuel gas through the ports 65, 66 andfiiiof the heads dg o f the blast'tips .20 so that these tips are extinguished; and i no flame jets are produced thereby. If, at anytime, it is desired to render agiven blast tip operative, it is. merely-necessary for the end ofthesleeve so as to define within the bore a relatively deep cylindrical socket establishing a combustion chamber, of a shut-off plug assembly removably disposed P within said socket; and substantially filling'the same when it is in use, said-shutoff plug assemblycomprising a composite laminated sealing plug proper consisting of a plurality of thin flexible flat annularwashers formed of heatresistant material and serially arranged in faceto-face operator to reach within the blast tip area and quickly pull the associated plug assembly 22 from its fnictionally lodged position within the combustion chamber 74. In-

stallation of a plug assembly 22to disablela given blast. V tip 26 may be effected by a reversal of this process, i.e.,

by reaching into the blast tip area and pushing one of the plug assemblies into position within the; combustion chamber of the selected -blast tip.' Since no -tools are required, as is the case when'individual stop cocks are. employed, there is no need for the operator to maintain his coaxial abutting relationship, saidwashers each having an outside diameter slightly greater than the diameterof said bore, an elongatedcylindrical rod-like handle for said sealingplug propen coaxial with said washers and having a circular end face abutting the foremost washer of the series, said end face of the handle. being provided with a threaded: socket centrally thereof, and a clamping bolt projecting through said washers, having an end thereof threadedly received in said socket, and an enlarged arm within the blast tip area any longer than it takes. to'

push or pull the plug assemblies 22 into or out of position. During core removal operations, where small core box sections are concerned, disabling of the blast'ti s 20 at the perimeter of the blast tip area will preclude reaching into the flame jet area anyfurther than they distance which is protected by the usual asbestosgloves of the operator. The use of the presentishutotf plug assemblies 22 will permit the positioning of the gas manifolds.

closer to the core boxsectionsthan has pheretofore been possible when individual shut-0E cocksare employed for the various blast tips.

The invention is not to be limited to the exact arrangeheadbearing against the rearrnost Washer of the series andserving to compress the medial regions of the washers together while allowing the peripheral regions thereof to remain free for sliding sealing engagement with the cylindrical bore, said shut-off plug assembly. being adapted to be manually. pushed into and pulled from said socket and adapted when in the socket to seal off said gas passages against theflow of fuel gas thercthrough.

Renew C d b th x mi er UNITED STATES PATENTS 1,696,09'1 '12/28- Kehl 158-274 2,090,943 8/37 Foster .Q 22-85 X 2,992,677 7/61 Williams a 158-117 QR GN R EN 11/52 France.

JAMES W. WESTHAVER, Primary Examiner.

JOHN]. CAMBY, Examiner. 

